Doesn't seem to matter much, since NN's are usually spoken things rather than written things, but I think Mo makes more sense if I was to spell it out as a NN for Amos. 'Mo' is right in there. And with a MN that starts with 'E', Moe almost looks like it should be MoE (mo-ee). AmosEmmanuel is awesome by the way. I actually prefer Amos without a middle name myself.